2 band pre or some type of volume boost?

Alright, so I have a single humbucker Peavey Forum that is supposed to have a 2 band pre. It has three knobs that one would assume are volume, bass, and treble.

What they really do is more like weak volume, volume boost, tone. The volume knob by itself makes the bass about half as loud as it can possibly be. The second knob makes it louder but has very little affect on the tone, and if the volume knob is rolled off this knob doesn't affect volume by itself. The third knob kind of acts like a tone knob with no real treble in it's range, so it does act like it could be expected to.